@mixin fullParent($pos: absolute) {
  position: $pos;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
}

@mixin selfCenter($pos: absolute) {
  position: $pos;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto;
}